1. Field of the Invention
The present invention relates to a device for fixing a work such as a liner guide rail in position.
2. Description of the Prior Art
A conventional device for fixing a liner guide rail will be hereinafter explained with reference to FIG. 12. In FIG. 12, a linear guide rail L is disposed on a surface S of a base B of a machine such as a machine tool. Recently, such linear guide rails L have also been frequently used in various machines and apparatus other than machine tools. The linear guide rail L is firstly positioned on the surface S of the base B in contact relationship with a reference surface R of the base B perpendicular to the surface S. A plurality of bolts V are subsequently inserted into a plurality of corresponding holes P formed in the linear guide rail L and are threadably engaged with corresponding threaded holes T formed on the base B so as to fix the linear guide rail L to the base B.
With this conventional device, the linear guide rail L may not uniformly contact the reference surface R for the following reasons:
(1) Inherent distortion of the linear guide rail L from linearity.
(2) Tolerance of design of the threaded holes T.
(3) Deformation of the bolts V when they have been tightened.
(4) Discordance of position between the holes P and their corresponding threaded holes T.
The non-uniform contact of the linear guide rail L with the reference surface R may degrade accuracy of positioning of the linear guide rail L, and therefore, the machine element to be guided cannot be linearly moved. Particularly, in case the linear guide rail is one used for guidance of a machine element of a machine tool for precision machining, such degraded positioning accuracy of the linear guide rail may lower the yield of the products and may cause many other drawbacks.
Further, the holes P of the linear guide rail L must be formed at a position precisely coincident with their corresponding threaded holes T, and such machining of the holes P is very troublesome. Additionally, when the linear guide rail L has been damaged or requires to be reformed, it is also necessary to reform the holes P, and such reformation of the holes P cannot be speedidly made.
Furthermore, in the fixing operation, the linear guide rail L must be positioned on the base B with the holes P aligned with the corresponding threaded holes T, respectively, and thereafter each of the bolts V is inserted into the corresponding hole P and is threadably engaged with the corresponding threaded hole T. Such operation is very troublesome.
In order to overcome the above-mentioned drawbacks, the prior art has proposed the use of pressing means which are effective for pressing the linear guide rail L laterally toward the reference surface R. The pressing means include a linear projection formed on the base B and extending in parallel with the reference surface R in spaced relation thereto in such a manner that the linear guide rail L may be positioned between the reference surface R and the linear projection. The pressing means further include a plurality of adjusting bolts threadably engaged with the linear projection in a direction perpendicular to the longitudinal direction thereof, so that the forward end of each of the adjusting bolts may be pressed on the corresponding lateral surface of the linear guide rail L so as to reform the same.
However, such a pressing device requires troublesome machining of the base B to form the projection. Further, since the adjusting bolts are to be moved in parallel with the horizontal surface of the base B, the operation of the adjusting bolts must be made within a limited space because of the presence of other machine elements, and in some case, it is not possible to operate the adjusting bolts. Therefore, this device cannot be generally utilized.